This study addressed the polarization among theoretical perspectives in moral psychology regarding the relative significance of parents and peers in children's developing moral maturity. The sample was composed of 60 target children from late childhood and midadolescence, 60 parents, and 60 friends who participated in parent/child and friend/child dyadic discussions of a series of moral conflicts. The quality of parents' and friends' verbal interactions, ego functioning, and level of moral reasoning in these discussions was used to predict the rate of children's moral reasoning development over a 4-year longitudinal interval. Results revealed that interactions with both parents and peers were predictive of children's development but that these two types of relationships influence development in rather different ways. Implications of the findings for the understanding of these socialization agents' roles in moral development are discussed.